Frequently Asked Questions
The following discussion is in no way exhaustive; rather it is an attempt to address a few of the frequently asked questions, and to stimulate thought and inquiry.
What is straw bale construction?
Straw bale construction generally speaking, is the use of normally discarded cereal grain straw to build the exterior walls of houses and commercial buildings.
What form is the straw in when used?
After the grain has been harvested, the straw is baled using the same balers that are used for baling hay.
How are the bales protected from the elements?
Bales are routinely sealed and protected by the use of stucco as well as lime and earth plasters.
What in the insulating value of straw bale construction?
The “R” value of a roughly two foot thick straw bale wall is measured in excess of 50, but the actual performance is probably beyond that.
What does a straw bale house cost?
Just as with any other house, the primary costs of construction are spread across the entire structure; including foundation, framing, roof, plumbing, electrical, and finishes. The use of straw bales does not magically make everything else in the house cheaper, and in most cases, the added labor and finishing of the bales will add around 15% to the cost. Each building must be individually priced in order to accurately assess costs.
What is rammed earth construction?
In most developed countries, rammed earth construction consists of blending screened materials from on-site excavation or from established gravel pits with a small percentage of cement, and compacting the material into forms similar to those used for concrete walls.
How old is rammed earth construction?
The basic principles of rammed earth construction go back millennia. In many parts of the world, buildings are still constructed in ways similar to how they have been built for hundreds or thousands of years. With the advent of modern excavating, screening, and tamping equipment, rammed earth has entered a new realm.
What is the benefit to using rammed earth?
When properly installed, rammed earth walls are not only beautiful, but add greatly to the energy efficiency and structure of the building.
What does rammed earth cost?
Even though the materials are generally cheaper to purchase that concrete, the added labor can add significantly to the cost of a building. Once again, each project must be reviewed individually.
How do straw bale and rammed earth construction effect carbon dioxide production or sequestration?
The obvious answer is, by constructing the walls of a building out of two feet of carbohydrates, you will tie up tons of carbon for the life of the building. Less energy is expended in the production of a lower percentage of cement in rammed earth construction as compared to concrete construction. Additional energy savings extend beyond these factors.